The expert estimates in the issue of the occurrence of used tyres reported their annual number to 700 million pieces of discarded tyres. The issue of their processing is solved throughout the duration of their use, but so far the results of the solution have not come into the capacity level of their occurrence. Used tyres, therefore, cumulate and become the environmental problem. The currently known technologies focus on the areas, of which the historically first appears to be the regeneration of the rubber by the action of superheated water vapour. The output is the so-called regenerate, which is used to additions into the rubber composition. Its production and the limited number of features compared to the original rubber, from which they arose, however, restrict this technology on a massive spread. The other direction in the technology of tyre processing is focused on the acquiring of rubber grit, which found its application/use in construction and in other areas, such as agriculture or engineering production. From these technologies are relatively well known the technologies using super-cooling of liquid nitrogen, when the rubber becomes fragile and then, in this state, it is disintegrated usually, in the hammer mills. Similar processing of rubber waste, when a mechanical shredder handles the deep-frozen rubber waste, is known for example from the document U.S. Pat. No. 5,735,471. Other technologies use for obtaining the grits the various types of mills. Both types of technologies require the prior removal of foot parts with the content of the steel wires, alternatively even cutting into smaller parts. This limits this technology for complex processing of used tyres.
Another procedure for the use of used tyres is in their combustion. A tyre is by its calorific value at the level of quality black coal, but by its mechanical composition, in particular the content of the steel reinforcements, it is for practical combustion for the purpose of obtaining energy, hard to use. A combustion furnaces for obtaining the heat water vapour, such as the Helnan-Freud's combustion furnace operating in Great Britain, allow you to burn the whole tyres, but only by batch way, since the removal of steel reinforcements from the furnace requires a shutdown of the device. The process therefore takes place by batch regime. A different and somewhat more modern method of tyre combustion arises from the system of oil burners and blowers, which, together with the rotary furnace, causes that the temperature rises in over 1300° C. and the steel sears and does not block the grates. The usability of such iron for recycling is sporadic.
A relatively trouble-free way to use tyres as a fuel is handled in the cement furnaces. Here the whole tyre will disappear and will be able to save other more expensive energy. The consumption of tyres in cement plants is, however, only a fraction of how many of them accumulate.
From the Czech utility model no. 20795 is further known a device for processing rubber waste, in particular tyres, by the physical-chemical process, which consists of at least one gas-tight chamber, into which by a feed pipe the aggressive gas is supplied, such as O3, moistened by the water mist, formed through at least one nozzle, to which the pressure water is brought from the tank. In the gas-tight chamber there are in lines one above the other, opposite each other, placed the top cylinders and contradictory bottom cylinders with a space for processed rubber waste. One from the lines of the cylinder is fixed, while the second of the lines of cylinders is vertically movable with pressure. On the input side of the gas-tight chamber there is located the input area with the input cap and the on output side there is located the output space with the output cap, whereas both spaces are provided with the output pipe with a against-explosive safety lock for exhaust of gas and both are from the internal space of the gas-tight chamber separated by internal closures. The disadvantage of this device is, in particular, in its relative complexity.
From the point of view of current technology knowledge it could appear the use of pyrolysis to be the final solution. The competent pyrolysis reactor for waste processing, in particular of tyres, it is known for example from the documents US 2011116986 or from the documents WO 9320396.
Pyrolysis, as it is performed in these devices, however, requires both relatively gently crushed input raw material, if possible, without any foreign admixtures, and also the external heating of the reactor. It moves the economy to a large burden of its own costs on grinding, and heating, so that the products are created only hardly, or with a small rate of profit they are in position to make the operations economically self-sufficient.